This invention relates generally to pseudo-random coded systems and, more particularly, concerns the supppression of autocorrelation sidelobes of a periodic phase-coded CW signal; for example, in CW and pulse-compression radar systems.
Radar employing pseudo-random coded (PRC) transmission and autocorrelation detection has the advantage of requiring a relatively low peak power on transmission, which permits the use of small and less costly transmitters.
The technical literature on the subject is extensive, and a background may be obtained from any of a number of texts; for example, the text MODERN RADAR by Raymond Berkowitz (John Wiley & Sons, Inc., publisher--1965).
In the presence of relatively near targets, the detection range of PRC radars is restricted due to the existence of sidelobes in the autocorrelation function of the phase code, the sidelobes of close target echoes being able to mask the echoes of more distant targets.
The general object of this invention is the provision of a device to suppress the autocorrelation sidelobes of a phase-coded periodic CW signal in order to overcome the above-mentioned problem.